1. Area of the Art
The invention relates to an ink development process, and particularly to an ink development process for the preparation of a pigmented ink.
2. Description of the Prior Art
The development of large format printing puts additional requirements on printing inks, such as exceptional durability and light fastness. To meet these requirements, conventional dyes are being replaced by the more heat and light resistant pigments such as quinacridones, phthalocyanines, and the like. These pigments are difficult to disperse. Preparation of good thermally stable dispersions with submicron particles is particularly difficult in the case of hot melt inks made on the basis of waxes. It requires longer milling time and powerful mills.
Usually the preparation of pigmented solid inks includes the milling of pigments in waxes in the presence of dispersing agents. This process is time and energy consuming and requires elaborate modem milling equipment. The resulting dispersion is often not stable, and an additional operation such as agitating the ink by shaking the printhead is needed to maintain good dispersion.
Therefore, a need exists to improve the milling process for obtaining a better pigment dispersion in a shorter time using relatively simple milling equipment.